Biology Flash Cards

Term:

tRNA

Description:

An abbreviation for Transfer RNA. As a Ribosome "reads" a messenger RNA (mRNA), it uses tRNAs to map the current codon (3 letter nucleotide sequence of the mRNA) to the next amino acid it needs to add to the protein. tRNA supplies this mapping between nucleotide sequences and protein sequences because it has both a 3-letter nucleotide sequence (which is complementary to the current mRNA codon) and also a specific amino acid. The mapping between 3-letter nucleotide sequences and amino acids provides the code of life.

See Also:

mRNA, Nucleotide, Amino Acid, Protein

Biology Definitions

A biologist studying cancer performs the following experiment. She puts normal cells into a petri dish, and exposes the petri dish to some kind of mutagen. The mutagen "transforms" some of the cells into cancer cells. These cancerous cells, which grow and divide in spite of contact inhibition, form "foci" which are easily visible in the petri dish. These foci are multi-layered, in contrast to the normal cells which form a single layer of cells on the bottom of the petri dish, and then stop growing and dividing due to contact inhibition.

Transform, Cancer, Contact Inhibition

Frequency of Non-Parental Types

A statistic used by Geneticists as a measure of Recombination Rate. Cross two individuals, count the number of offspring who have phenotypes indicating that they received a chromosome that has undergone Genetic Recombination. Divide this number by the total number of children to get the Frquency of Non-Parental Types. The terms "Recombination Rate" and "Frequency of Non-Parental Types" are sometimes used interchangeably.